Determinação do coeficiente de cultivo da cana-de-açúcar de ano

Abstract

Sugarcane has its production focus in the southeastern and northeastern region of Brazil, but due to the growing demand for biofuels and its value in the national and international market, its production has expanded throughout Brazil. To ensure maximum production, coupled with the rational and sustainable use of water, it is necessary to study the real water demand of the crop. For this purpose, this work was carried out under field conditions at Embrapa Agropecuária Oeste - Dourados, MS, during the 2018/19 harvest, in order to determine the crop coefficient (Kc), evaporation coefficient (Ke) and basal crop coefficient (Kcb) for yearold sugarcane. The crop evapotranspiration (ETc) was measured by a weighing lysimeter, where sugarcane was grown on its surface and border (total area of 0.55 ha). For the determination of the single and dual coefficients, it was necessary to use the reference evapotranspiration (ET0), obtained by means of the Penman-Monteith equation, with the variables collected at the agrometeorological station of Embrapa Agropecuária Oeste. Microlisimeters were installed near the lysimeter and used for determination of evaporation (E) and, consequently, the difference between ETc and E, the transpiration (T) was determined. The values of the coefficients were analyzed together with the leaf area index (LAI) of the crop. The values obtained from the coefficients were: for the initial phase, Kc of 0.7, Ke 0.4 and Kcb 0.2; whereas at the development stage these values were, Kc of 1.0, Ke 0.3 and Kcb 0.7.